What is Nonpoint Source Pollution?
Nonpoint source pollution is another term for polluted runoff.
Water washing over the land, whether from rain, landscape watering,
car washing, or any other source, picks up an array of contaminants
including oil and sand from roadways, and toxic materials from
urban and suburban areas. This runoff may eventually find its
way into our waterways, either directly or through storm drain
collection systems.
The term nonpoint is used to distinguish this type of pollution
from point source pollution, which comes from specific sources
such as sewage treatment plants or industrial facilities. Although
major strides have been made in cleaning up major point sources,
our water resources are still affected by polluted runoff. The
U.S. Environmental Protection Agency estimates that this type
of pollution is a leading cause of the deterioration of water
quality nationwide.
Why Should I Care About Nonpoint Source Pollution?
The effects of polluted runoff are not limited to large lakes
or coastal bays. Even here in the desert, nonpoint source pollution
impacts the quality of our rivers. Concern over polluted runoff
has resulted in an ever-increasing number of regulations enacted
over the last five years. At federal and state levels, a permit
program for storm water discharges from certain businesses and
municipalities is underway. Pima County and the City of Tucson
are both working to comply with those regulations. The bottom
line is that both polluted runoff and its management are likely
to affect you and your community in the near future.
What Causes Polluted Runoff?
You do. We all do. Polluted runoff is the cumulative result
of our everyday personal actions and our local land use policies.
Here's a brief rundown on the causes and effects of the major
types of pollutants carried by runoff.
Pathogens: Pathogens are disease-causing microorganisms, such
as bacteria and viruses, that come from the fecal waste of humans
and animals. Pathogens wash off the land from wild animal, farm
animal and pet waste, and can also enter our waterways from improperly
functioning septic tanks and leaky sewer lines.
Nutrients: Nutrients are compounds that stimulate plant growth,
like nitrogen and phosphorous. Under normal conditions, nutrients
are beneficial and necessary, but in high concentrations, they
can become an environmental threat. Nitrogen contamination of
drinking water can cause health problems, including "blue
baby" syndrome. Nutrients in polluted runoff can come from
agricultural fertilizers, septic systems, home lawn care products,
and yard and animal wastes.
Sediment: Sand, dirt and gravel eroded by runoff clog ditches,
culverts and drain pipes and create the potential for flooding.
Poorly protected construction sites and unpaved roads can be
major sources of sediment.
Toxic Contaminants: Toxic contaminants are substances that can
harm the health of aquatic life and/or human beings. Toxins are
created by a wide variety of human practices and products, and
include heavy metals (lead, zinc, copper, etc.), pesticides and
organic compounds. Many toxins are resistant to breakdown and
tend to be passed through the food chain. Oil, grease and gasoline
from roadways, and chemicals used in homes, gardens, and yards
are major sources of toxic contaminants.
Debris: Trash is without a doubt the simplest type of pollution
to understand. It interferes with enjoyment of our water resources.
Here in Pima County, our dry washes become a convenient place
for the illegal dumping of debris. During the next storm, when
water flows through that wash, the waste will be swept downstream,
perhaps into your neighborhood.
What Can I Do?
Pollution
prevention is the key to decreasing nonpoint source
pollution. You can begin at home with simple but important things.
Conserve Water: When watering your yard, make sure that you
apply just enough water without allowing excess water to flow
down the driveway or into the street. Water flowing over the
land picks up an array of contaminants.
Limit the Use of Pesticides and Herbicides: Use household and
garden chemicals only when necessary and follow the manufacturer's
directions to apply the correct amounts.
Properly Dispose of Household Hazardous Waste: Many products
around the house can be considered hazardous waste and should
be disposed of properly. For more information, see Household
Hazardous Waste.
Report Illegal Dumping: If you see an illegal dumpsite, call
the Illegal Dumping Hotline to report it. For more information,
see Illegal Dumping.
The EPA also provides information about managing nonpoint
source pollution from households.
